Newborn infants are routinely tested for various genetic disorders. These tests are expensive, and typically only a small fraction of possible disorders are included in the testing regimen. At least 50 lysosomal storage disorders are rarely tested. Some of these disorders are extremely rare. Pathologies often involve significant physical and mental debilitation leading to death. Therapies are available in some cases. Outcomes may be improved with early diagnosis and treatment. Pompe disease, for example, results from a deficiency in alpha-glucosidase. Enzyme replacement therapy is available for treating the condition. However, newborns are rarely screened for Pompe.
Testing of newborn infants typically involves collecting a sample of blood from the heel of a baby. The sample is placed on a card, dried to yield a dried blood sample (DBS). The DBS is transported to a central laboratory for testing, where it is used as input for assays for several metabolic and other disorders. Using the current DBS testing methodologies, a prohibitively large volume of blood would be required in order to do a significantly larger number of tests.
There is a need for testing methods that are highly sensitive and require only a small volume of blood.
Droplet actuators are used to effect droplet operations. A droplet actuator typically includes one or more substrates configured to form a droplet operations surface or gap for conducting the droplet operations. The one or more substrates may be associated with electrodes for mediating the droplet operations. The droplet operations surface or gap is typically filled or coated with a filler fluid that is immiscible with the liquid that is to be subjected to droplet operations. There is a need in the art for techniques for conducting enzyme assays which make use of the advantages of droplet actuators.